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Cartilage injuries are well known to be troublesome and difficult to treat. Such injuries are partial and full thickness lesions most often easily detectable on MRI scanning. However, less well-known are lesions that start between the calcified bone (in the calcified zone) and the bone plate and they are called chondral delaminations. Such lesions often take time to detect. If not found and treated they may develop into full thickness lesions. In a short review, the diagnosis and treatment alternatives are discussed.
In this type of injury, the forces affect the different layers in the cartilage so that the greatest weakness lies in the layer between the calcified cartilage and other cartilage. The damage goes deep down but usually does not expose the bone plate. A crush damage more or less destroys the various layers in the vertical direction. However, most injuries are a combination of rotation and direct vertical forces. Not so well-known but important is the damage that occurs between the calcified bone (in the calcified zone) and the bone plate. This is called chondral delamination. It is difficult to diagnose and if noticed late, a more severe chondral lesion may develop with eruption to an open lesion. The intact superficial cartilage layer will be unstable and strong shearing forces on the edges of the delamination may lead to either enlargement of the delamination or fissuring. Finally, such a delamination develops into a full thickness defect ICRS grade 3c. Many full thickness defects could have been localized chondral delaminations initially.
In this paper, the trauma mechanisms, clinical symptomatology, clinical and radiologic diagnostics and treatments are discussed.
Trauma mechanisms
Mathematical and computational modeling calculations on cartilage as a tissue could improve our understanding of cartilage aging, pathology, reaction to trauma and intervention.
With such calculations, a biphasic model was developed where articular cartilage is composed of a fluid phase and a solid skeleton to represent the mechanical behavior of cartilage.
The biphasic model has by time been extended to become triphasic in order to also look upon several aspects of the cartilage structure and physiology including depth dependent collagen fiber distribution and orientation, aggrecan density and structural anisotropies.
With the help of the different theoretical models, calculations have shown that highest shear stresses occur at the interface with bone, and that normal stresses are compressive near the surface in the zone of contact.
have shown that so-called “occult microcracks” appear at the cartilage-bone interface after a blunt trauma and that adult articular cartilage may show significant alterations in its histological, biochemical, and ultrastructural characteristics without disruption of the articular surface. Armstrong et al
could demonstrate in a pig model with blunt trauma appearance of a cartilage separation from subchondral bone in the patellofemoral joint. However, in similar experiments reported by Haut et al
the authors did not find cartilage–bone interface separation presumably due to a different direction of the blunt trauma being more medial. Subsequently, the injury pattern can vary depending on different trauma directions as also been shown by Ewers et al.
showed in a pig model that when a shear force was applied on a joint at high speed but with low energy, the articular cartilage surface was the first to crack. At low speed and low energy, splits occurred in the deeper layers first. Broom et al
further demonstrated that a mature cartilage tissue delaminates within a well-defined tidemark region while the immature cartilage fractures through the subchondral bone into which fingers of articular cartilage penetrate. In another research, the same group
also found that shear fractures in the immature tissue always occurred subchondrally as a discontinuous propagation of a relatively large, fast moving crack. By contrast, failure in the skeletally mature tissue occurred by a more rapid advance of a smaller crack which propagated within the well-defined tidemark region.
The difference in vitro and in vivo experimental models of articular cartilage "contusion" may subsequently show similarities to the clinical joint damage that is observed following direct blunt trauma transmitted across articular surfaces without radiographic evidence of fracture. Similar damage has been shown to occur from direct shear loading.
Rotational and shearing forces on a small area of the cartilage tissue could traumatize the region between either the superficial part of the tidemark or the deep part of calcified cartilage (immature) and the superficial part of the bone plate. The superficial delamination will not induce a bleeding while the deep ones most often start an intracortical bleeding which may further separate cartilage from bone. In both types of lesions, overlying cartilage will be slightly elevated and very soft. The deep lesions will mostly be seen in young patients who have not yet developed a calcified zone. Chondral delamination could also be seen in cases with localized osteonecrosis. Especially in elderly patients and early OA, also osteonecrosis may develop after a minor trauma and could fast develop into an open lesion.
Treatable chondral injuries in the knee: frequency of associated focal subchondral edema. AJR 2000 BT, Francavilla ML. MRI of Native Knee Cartilage Delamination Injuries.
have further speculated that chondral delamination could be part of a subcortical “ischemic insult.” Also, blisters seen in degenerative joints may have been started as localized delaminations initially.
The blisters are totally empty under their surfaces with lack of chondral tissues down to bone. Decreased vascularity seen in patients with sickle cell anemia induce bone infarction. Overlying cartilage can be intact in early stages. However, large areas of cartilage delamination similar to the traumatic defects may be evident along with hemosiderin lining of the synovium similar to the bleeding disorders.
Some chondral delaminations are found in conjunction with posterior horn injuries of the medial meniscus and at patella or trochlear areas after shear or blunt injuries.
Furthermore, delamination of the chondral surface of an osteochondral allograft (OCA) from the underlying cancellous bone has been described as a mode of failure after implantation in the knee.
However, there are also many cases of chondral delaminations without any obvious traumatic event to be coupled to the findings. Constitutional factors like different anatomical forms of the condyles and dysplasias may be involved.
Symptomatology
Patients often complain of localized knee joint and weight bearing pain and there is seldom any history of a clear joint trauma. However, some patients describe a slight rotation of the joint in flexion as the start of pain. The knee flexion angle plays an important role in impact related knee trauma.
Local tenderness may exist but there are often very few clinical findings.
Radiology
A low sensitivity of imaging identification of delamination injury of the knee is reported in the available literature. Most often a plain x-ray will not show any pathology. A slight localized bone reaction may appear in late cases. On MR imaging, the delamination is seen as buckling or deformation of the cartilage with/without T2 hyperintense fluid signaling intensity dissecting between the cartilage and the subchondral bone.
At early stages, MRI may show intact cartilage but slightly uplifted with signals below indicating bleeding and often bone marrow increased signals. At later stages, tears from the area extending from the bone to cartilage surface may be noticed (Fig. 1A and B).
Fig. 1A: Sagittal MRI view of a large medial femoral condyle chondral delamination. B: Coronal MRI of the same medial femoral condyle chondral delamination.
It has been difficult to differentiate the radial layer from the calcified layer because of their low T2 values. However, with ultrashort TE pulse sequences acquiring signals from those tissues short T2 components and with their differences in mobile protone density, differentiation of deep layers is possible.
could demonstrate that chondral delaminations show increased linear signal abnormality at the junction of the articular cartilage and subchondral bone on T2-weighted (fast spin-echo) images of the knee. The lesions could be identified with a thin line of near–fluid intensity interposed between the cartilage deep layers and the bone.
suggest use of intermediate-weighted sequences that combine the contrast advantage of proton density weighting with that of T2 weighting by using a TE of 33 to 60 msec. Such sequences provide a higher total signal intensity in cartilage than standard T2-weighted sequences do and by that, allowing better differentiation between cartilage and subchondral bone.
recently suggested the use of a combination of orthogonally acquired 2D FSE sequences, including fat-suppressed T2-weighted and PD-weighted sequences, and a sagittal fat-suppressed DESS sequence. Loss of the laminar appearance has been reported in association with chondral lesions of the retropatellar cartilage
Upon arthroscopic inspection, the visual cartilage surface looks intact, however, with an indentation probe, one can detect a locally reduced elasticity, increased softness and sometimes an area can be seen only as a bulging of the cartilage surface. These often small but treacherous injuries can be very painful due to the developed hematoma in the pouch under the delaminated, uplifted cartilage layer. You may then need to empty the hematoma. This may be done from a retrograde or an antegrade direction. Eventually, this type of injury can develop into a blister. Blisters are graded as ICRS Grade III d 26 and pure chondral delaminations should also be classified as ICRS Grade III d lesions as the treatment most often is the same.
If there is only a localized cartilage surface softness, one may use a thin needle to enter through the cartilage. Often a small stream of blood comes from the needle hole indicating the delamination area with a hematoma (Fig. 2A-C). A blister region is more obvious by sight. With a light pressure with an arthroscopy probe, the instrument's tip comes straight through the blistering or the soft area and you can then note that it is empty under the softness/blister and the probe tip ends up directly against the bone, that is, it is a deep but local injury (Fig. 3A and B). Also from blisters a brownish fluid of old blood then often empties from the damaged area (Fig. 4A-C). It might be useful to describe the delamination using a classification related to the involved area. With such a classification, it could be easier to choose treatments.
Fig. 2A: Drawing of a chondral delamination with a small bleeding starting to fill the delaminated space. B: The delaminated space has been completely filled up with a hematoma. C: With a thin needle inserted through the uplifted cartilage to the bone, the hematoma could be evacuated.
Fig. 3A: Photo of a delaminated area. The indentation probe finds the soft spot overlying the delaminated area. B: With a slight press on the tip of the probe, the probes enter easily into the delaminated space and blood is evacuated.
Fig. 4A: Photo of a blister. B: With a slight compression with a probe, the blister protrudes a bit more. C: With a slight press on the tip of the probe, the probes enter easily through the blister and blood is evacuated.
Grade 3: Cartilage softness with fissures through cartilage down to bone
Grade 4: Full open defect
With a small area of cartilage softness/blister area, a focal debridement of the soft area will immediately turn surrounding cartilage stable while larger areas need a more extensive debridement of cartilage to turn surrounding cartilage stable. The author's experience is that small areas can be treated with just debridement while defects larger than 5 mm need a complete repair to be stabilized. Considering that the mean bicondylar width of the femur has been shown found to be 8.39 cm ± 0.63 cm, defects larger than 5 mm on a condyle are quite large defects.
described chondral delaminations in soccer players. However, those lesions were already at time of operation open chondral defects and according to the above proposed CD-classification grade 4 to 5. In their radiology paper from 2005, Kendell et al
described 5 patients with chondral delamination but no more precise information about type of surgical treatment was described. Mean patient age was 26.4 (16-37) years, lesion size from 0.5 to 2.5 cm with the locations on medial femoral condyle, trochlea and patella.
were the first to present treatment suggestions for chondral delamination. A case series of 3 patients (12-36 years of age) with knee pain and MRI identified chondral delaminations were presented. Two of the lesions were located in the patella and one on the lateral aspect of the medial femoral condyle. All 3 lesions were treated with bioabsorbable pin fixation.
The delaminated area was easily recognized at arthroscopy by its swampy character on probing. The condyle patient was mobilized with non-weight bearing for 6 weeks and with static isometric quadriceps exercises undertaken from the outset. Loaded flexion was allowed from 12 weeks. One patellar lesion patient was placed in a range of motion brace 0 to 30° and advised to mobilize weight bearing as tolerated the first 6 weeks. The brace was removed for unrestricted range of flexion while not under load. All 3 patients recovered well clinically and the lesions healed on MRI.
A totally loose delaminated cartilage piece can be attached as described by an all arthroscopic suture-bridge fixation with the use of pushlock anchors.
The author of this paper treats the chondral delamination depending on the size of lesion, patient age and level area of the separation, above or in the calcified layer or below the calcified layer. If the chondral delamination has occurred in a child or adolescent with no calcified layer developed, often a small thin wafer of the bone plate may be attached to the delaminated cartilage. If the delamination is not too large, re-fixation with resorbable pins is then an option (Fig. 5A and B).
Fig. 5A: A drawing of the delaminated area after hematoma evacuation. The area is still soft and moveable and needs to be fixated to the bone. B: The delaminated area has been fixated with resorbable smartnails. Such a fixation may be done in a triangular fashion. C: If large delaminated area, additional corner sutures might be needed. D: A delaminated area has not been treated and one of the corner bridges to surrounding non-delaminated cartilage has been broken. A full thickness area will develop needing more aggressive cartilage repair.
First, the region is emptied from the hematoma by needle aspiration followed by pin fixation, mostly smart nails (ConMed). If the delamination area is large, mini-open surgery may be needed and complimentary osteo-sutures could be used (Fig. 5A and B). If it is not an option to re-fixate (Fig. 5C), just the soft spot area is debrided (Fig. 6A). The lesion area is then debrided as like an ordinary ICRS III lesion. If it is a small lesion, most often bone marrow stimulation is done (Fig. 6B). If it is a larger lesion, an additional scaffold may be used like Hyalofast (ANICA).
Fig. 6A: If the delaminated area is not suitable for refixation, the delaminated needs to be excised. For small injured areas, excision with a small punch is easily performed. B: A small delamination area is treated with bone marrow stimulation after debridement. A 2 mm burr is used.
Fragments can be harvested from the soft delamination cartilage. Dehydrated, micronized allogeneic cartilage that can be implanted with platelet-rich plasma into cartilage defects is also an alternative.
After debridement, it can be noted that the surrounding cartilage has regained its elasticity.
It is very important to understand that even though MRI did not show any pathology, a patient with a localized knee pain, could have a localized chondral delamination. In cases with sustainable pain, careful probing of the cartilage areas is mandatory.
Discussion
Patients seeking orthopedic evaluation due to joint pain, post-trauma or without traumatic history are most often examined by MRI. If nothing is found on MRI, the patients are scheduled for physiotherapy. However, if in spite of long time training, the patient still is in pain, often the next step is an arthroscopy. Prior to an arthroscopy, one may add a scintigraphic evaluation like a pure technetium scan or a SPECT.
Such a scan may show an increased uptake locally in the joint which will help the surgeon performing the arthroscopy to focus on the area of scintigraphic uptake. The incidence of chondral delamination injuries of the knee has not been reported in the literature. Already in 1985, Hopkinson et al
described a group of patients presenting with meniscal symptoms of who, on arthroscopic examination, had chondral fractures of the medial or lateral femoral condyle. The authors felt it was important to discuss the chondral fracture so that the orthopedic surgeon could be aware this injury type.
Since then, better diagnostics have been introduced with different MRI sequences but still chondral delaminations may be difficult to diagnose. Delamination injuries of cartilage can lead to significant morbidity if they are not treated early. This means that delay in finding such lesions may lead to early OA and more aggressive treatments. If a patient is claiming a significant pain in certain degrees of joint flexion, suspicion of local delamination is adequate and an arthroscopy is indicated, though the MRI is negative.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Declaration of competing interest
I am a member of the advisory board for Episurf Medical AB. I have been on the speaker's bureau for Arthrex during 2021. I have consultancies for Xintela AB and for Finceramica during 2021. I am editor in chief of Journal CARTILAGE.
Treatable chondral injuries in the knee: frequency of associated focal subchondral edema. AJR 2000 BT, Francavilla ML. MRI of Native Knee Cartilage Delamination Injuries.
A: Drawing of a chondral delamination with a small bleeding starting to fill the delaminated space. B: The delaminated space has been completely filled up with a hematoma. C: With a thin needle inserted through the uplifted cartilage to the bone, the hematoma could be evacuated.
A: Photo of a delaminated area. The indentation probe finds the soft spot overlying the delaminated area. B: With a slight press on the tip of the probe, the probes enter easily into the delaminated space and blood is evacuated.
A: Photo of a blister. B: With a slight compression with a probe, the blister protrudes a bit more. C: With a slight press on the tip of the probe, the probes enter easily through the blister and blood is evacuated.
A: A drawing of the delaminated area after hematoma evacuation. The area is still soft and moveable and needs to be fixated to the bone. B: The delaminated area has been fixated with resorbable smartnails. Such a fixation may be done in a triangular fashion. C: If large delaminated area, additional corner sutures might be needed. D: A delaminated area has not been treated and one of the corner bridges to surrounding non-delaminated cartilage has been broken. A full thickness area will develop needing more aggressive cartilage repair.
A: If the delaminated area is not suitable for refixation, the delaminated needs to be excised. For small injured areas, excision with a small punch is easily performed. B: A small delamination area is treated with bone marrow stimulation after debridement. A 2 mm burr is used.
Cartilage injuries are well known to be troublesome and difficult to treat. Such injuries are partial and full thickness lesions most often easily detectable on MRI scanning. However, less well-known are lesions that start between the calcified bone (in the calcified zone) and the bone plate and they are called chondral delaminations. Such lesions often take time to detect. If not found and treated they may develop into full thickness lesions. In a short review, the diagnosis and treatment alternatives are discussed.
When a cartilage surface is damaged, it often occurs via a rotational movement with a force coming from the side or as a direct force.1x1Buckwalter, J.A. Mechanical injuries of articular cartilage. Iowa Orthoepy J. 1992;
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280: 21–38 Crossref | PubMed | Scopus (63) | Google ScholarSee all References In this type of injury, the forces affect the different layers in the cartilage so that the greatest weakness lies in the layer between the calcified cartilage and other cartilage. The damage goes deep down but usually does not expose the bone plate. A crush damage more or less destroys the various layers in the vertical direction. However, most injuries are a combination of rotation and direct vertical forces. Not so well-known but important is the damage that occurs between the calcified bone (in the calcified zone) and the bone plate. This is called chondral delamination. It is difficult to diagnose and if noticed late, a more severe chondral lesion may develop with eruption to an open lesion. The intact superficial cartilage layer will be unstable and strong shearing forces on the edges of the delamination may lead to either enlargement of the delamination or fissuring. Finally, such a delamination develops into a full thickness defect ICRS grade 3c. Many full thickness defects could have been localized chondral delaminations initially.
In this paper, the trauma mechanisms, clinical symptomatology, clinical and radiologic diagnostics and treatments are discussed.
Trauma mechanisms
Mathematical and computational modeling calculations on cartilage as a tissue could improve our understanding of cartilage aging, pathology, reaction to trauma and intervention.3x3Armstrong, C.G. An analysis of the stresses in a thin layer of articular cartilage in a synovial joint. Eng Med. 1986;
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The clinical chondral injury
Rotational and shearing forces on a small area of the cartilage tissue could traumatize the region between either the superficial part of the tidemark or the deep part of calcified cartilage (immature) and the superficial part of the bone plate. The superficial delamination will not induce a bleeding while the deep ones most often start an intracortical bleeding which may further separate cartilage from bone. In both types of lesions, overlying cartilage will be slightly elevated and very soft. The deep lesions will mostly be seen in young patients who have not yet developed a calcified zone. Chondral delamination could also be seen in cases with localized osteonecrosis. Especially in elderly patients and early OA, also osteonecrosis may develop after a minor trauma and could fast develop into an open lesion.23x23Kolb, A.R., Patsch, J.M., Vogl, W.D. et al. The role of the subchondral layer in osteonecrosis of the femoral head: analysis based on HR-QCT in comparison to MRI findings. Acta Radiol. 2019;
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Some chondral delaminations are found in conjunction with posterior horn injuries of the medial meniscus and at patella or trochlear areas after shear or blunt injuries.31x31Mosher, T.J. MRI of osteochondral injuries of the knee and ankle in the athlete. Clin Sports Med. 2006;
25: 843–866 Abstract | Full Text | Full Text PDF | PubMed | Scopus (24) | Google ScholarSee all References Furthermore, delamination of the chondral surface of an osteochondral allograft (OCA) from the underlying cancellous bone has been described as a mode of failure after implantation in the knee.32x32Rauck, R.C., Wang, D., Tao, M., and Williams, R.J. Chondral delamination of fresh osteochondral allografts after implantation in the knee: a matched cohort analysis. Cartilage. 2021;
10: 402–407 Crossref | Scopus (8) | Google ScholarSee all References
However, there are also many cases of chondral delaminations without any obvious traumatic event to be coupled to the findings. Constitutional factors like different anatomical forms of the condyles and dysplasias may be involved.
Symptomatology
Patients often complain of localized knee joint and weight bearing pain and there is seldom any history of a clear joint trauma. However, some patients describe a slight rotation of the joint in flexion as the start of pain. The knee flexion angle plays an important role in impact related knee trauma.33x33Atkinson, P.J. and Haut, R.C. Injuries produced by blunt trauma to the human patellofemoral joint vary with flexion angle of the knee. J Orthop Res. 2001;
19: 827–833 Crossref | PubMed | Scopus (24) | Google ScholarSee all References Local tenderness may exist but there are often very few clinical findings.
Radiology
A low sensitivity of imaging identification of delamination injury of the knee is reported in the available literature. Most often a plain x-ray will not show any pathology. A slight localized bone reaction may appear in late cases. On MR imaging, the delamination is seen as buckling or deformation of the cartilage with/without T2 hyperintense fluid signaling intensity dissecting between the cartilage and the subchondral bone.34x34Omoumi, P., Teixeira, P., Delgado, G., and Chung, C.B. Imaging of lower limb cartilage. Top Magn Reson Imaging. 2009;
20: 189–201 Crossref | PubMed | Scopus (6) | Google ScholarSee all References
At early stages, MRI may show intact cartilage but slightly uplifted with signals below indicating bleeding and often bone marrow increased signals. At later stages, tears from the area extending from the bone to cartilage surface may be noticed (Fig. 1Fig. 1A and B).
Fig. 1
A: Sagittal MRI view of a large medial femoral condyle chondral delamination. B: Coronal MRI of the same medial femoral condyle chondral delamination.
T2 values of hyaline cartilage are varying from the superficial to deep layers.34x34Omoumi, P., Teixeira, P., Delgado, G., and Chung, C.B. Imaging of lower limb cartilage. Top Magn Reson Imaging. 2009;
20: 189–201 Crossref | PubMed | Scopus (6) | Google ScholarSee all References It has been difficult to differentiate the radial layer from the calcified layer because of their low T2 values. However, with ultrashort TE pulse sequences acquiring signals from those tissues short T2 components and with their differences in mobile protone density, differentiation of deep layers is possible.35x35Bydder, G.M. and Chung, C.B. Magnetic resonance imaging of short T2 relaxation components in the musculoskeletal system. Skeletal Radiol. 2009;
38: 201–205 Crossref | PubMed | Scopus (11) | Google ScholarSee all References,36x36Robson, M.D., Gatehouse, P.D., Bydder, M., and Bydder, G.M. Magnetic resonance: an introduction to ultrashort TE (UTE) imaging. J Comput Assist Tomogr. 2003;
27: 825–846 Crossref | PubMed | Scopus (534) | Google ScholarSee all References
Kendell et al37x37Kendell, S.D., Clyde, A.H., Rampton, J.W., Garrett, W.E., and Higgins, L.D. MRI appearance of chondral delamination injuries of the knee. AJR Am J Roentgenol.2005;
184: 1486–1489 Crossref | PubMed | Scopus (37) | Google ScholarSee all References could demonstrate that chondral delaminations show increased linear signal abnormality at the junction of the articular cartilage and subchondral bone on T2-weighted (fast spin-echo) images of the knee. The lesions could be identified with a thin line of near–fluid intensity interposed between the cartilage deep layers and the bone.17x17Tomatsu, T., Imai, N., Takeuchi, N., Takahashi, K., and Kimura, N. Experimentally produced fractures of articular cartilage and bone. The effects of shear forces on the pig knee. J Bone Joint Surg Br. 1992;
74: 457–462 Crossref | PubMed | Google ScholarSee all References A bone marrow edema signal could often be present and could be ahelp when identifying the site of the lesion.37x37Kendell, S.D., Clyde, A.H., Rampton, J.W., Garrett, W.E., and Higgins, L.D. MRI appearance of chondral delamination injuries of the knee. AJR Am J Roentgenol.2005;
184: 1486–1489 Crossref | PubMed | Scopus (37) | Google ScholarSee all References Fat suppression techniques provide increased contrast at the subchondral bone–cartilage interface.38x38Crema, M.D., Roemer, F.W., Marra, M.D. et al. Articular cartilage in the knee: current MR imaging techniques and applications in clinical practice and research. RadioGraphics. 2011;
31: 37–61 Crossref | PubMed | Scopus (324) | Google ScholarSee all References Crema et al38x38Crema, M.D., Roemer, F.W., Marra, M.D. et al. Articular cartilage in the knee: current MR imaging techniques and applications in clinical practice and research. RadioGraphics. 2011;
31: 37–61 Crossref | PubMed | Scopus (324) | Google ScholarSee all References suggest use of intermediate-weighted sequences that combine the contrast advantage of proton density weighting with that of T2 weighting by using a TE of 33 to 60 msec. Such sequences provide a higher total signal intensity in cartilage than standard T2-weighted sequences do and by that, allowing better differentiation between cartilage and subchondral bone.38x38Crema, M.D., Roemer, F.W., Marra, M.D. et al. Articular cartilage in the knee: current MR imaging techniques and applications in clinical practice and research. RadioGraphics. 2011;
31: 37–61 Crossref | PubMed | Scopus (324) | Google ScholarSee all References White et al25x25White, C.L., Chauvin, N.A., Waryasz, G.R., March, B.T., and Francavilla, M.L. MRI of native knee cartilage delamination injuries. Am J Roentgenol. 2017;
209: 317–321 Crossref | PubMed | Scopus (10) | Google ScholarSee all References recently suggested the use of a combination of orthogonally acquired 2D FSE sequences, including fat-suppressed T2-weighted and PD-weighted sequences, and a sagittal fat-suppressed DESS sequence. Loss of the laminar appearance has been reported in association with chondral lesions of the retropatellar cartilage39x39Uhl, M., Ihling, C., Allmann, K.H. et al. Human articular cartilage: in vitro correlation of MRI and histologic findings. Eur Radiol. 1998;
8: 1123–1129 Crossref | PubMed | Scopus (53) | Google ScholarSee all References and cartilage elsewhere in the knee, 40 and may also reflect early degeneration or predict future delamination.40x40Gold, S.L., Burge, A.J., and Potter, H.G. MRI of hip cartilage: joint morphology, structure, and composition. Clin Orthop. 2012;
470: 3321–3331 Crossref | PubMed | Scopus (53) | Google ScholarSee all References,41x41Potter, H.G. and Koff, M.F. MR imaging tools to assess cartilage and joint structures. HSS J. 2012;
8: 29–32 Crossref | PubMed | Scopus (15) | Google ScholarSee all References
Arthroscopic diagnosis and treatment
Arthroscopic diagnosis
Upon arthroscopic inspection, the visual cartilage surface looks intact, however, with an indentation probe, one can detect a locally reduced elasticity, increased softness and sometimes an area can be seen only as a bulging of the cartilage surface. These often small but treacherous injuries can be very painful due to the developed hematoma in the pouch under the delaminated, uplifted cartilage layer. You may then need to empty the hematoma. This may be done from a retrograde or an antegrade direction. Eventually, this type of injury can develop into a blister. Blisters are graded as ICRS Grade III d 26 and pure chondral delaminations should also be classified as ICRS Grade III d lesions as the treatment most often is the same.26x26Brittberg, M. and Winalski, C.S. Evaluation of cartilage injuries and repair. J Bone Joint Surg Am. 2003;
85-A: 58–69 Crossref | PubMed | Scopus (953) | Google ScholarSee all References
If there is only a localized cartilage surface softness, one may use a thin needle to enter through the cartilage. Often a small stream of blood comes from the needle hole indicating the delamination area with a hematoma (Fig. 2Fig. 2A-C). A blister region is more obvious by sight. With a light pressure with an arthroscopy probe, the instrument's tip comes straight through the blistering or the soft area and you can then note that it is empty under the softness/blister and the probe tip ends up directly against the bone, that is, it is a deep but local injury (Fig. 3Fig. 3A and B). Also from blisters a brownish fluid of old blood then often empties from the damaged area (Fig. 4Fig. 4A-C). It might be useful to describe the delamination using a classification related to the involved area. With such a classification, it could be easier to choose treatments.
Fig. 2
A: Drawing of a chondral delamination with a small bleeding starting to fill the delaminated space. B: The delaminated space has been completely filled up with a hematoma. C: With a thin needle inserted through the uplifted cartilage to the bone, the hematoma could be evacuated.
A: Photo of a delaminated area. The indentation probe finds the soft spot overlying the delaminated area. B: With a slight press on the tip of the probe, the probes enter easily into the delaminated space and blood is evacuated.
A: Photo of a blister. B: With a slight compression with a probe, the blister protrudes a bit more. C: With a slight press on the tip of the probe, the probes enter easily through the blister and blood is evacuated.
Grade 3: Cartilage softness with fissures through cartilage down to bone
Grade 4: Full open defect
With a small area of cartilage softness/blister area, a focal debridement of the soft area will immediately turn surrounding cartilage stable while larger areas need a more extensive debridement of cartilage to turn surrounding cartilage stable. The author's experience is that small areas can be treated with just debridement while defects larger than 5 mm need a complete repair to be stabilized. Considering that the mean bicondylar width of the femur has been shown found to be 8.39 cm ± 0.63 cm, defects larger than 5 mm on a condyle are quite large defects.42x42Terzidis, I., Totlis, T., Papathanasiou, E., Sideridis, A., Vlasis, K., and Natsis, K. Gender and side-to-side differences of femoral condyles morphology: osteometric data from 360 Caucasian Dried Femori. Anat Res Int. 2012;
: 1–6 (2012679658) Google ScholarSee all References
Treatment
There are very few descriptions of how to treat chondral delaminations. In 1996, Levy et al43x43Levy, A.S., Lohnes, J., Sculley, S., LeCroy, M., and Garrett, W. Chondral delamination of the knee in soccer players. Am J Sports Med. 1996;
24: 634–639 Crossref | PubMed | Scopus (186) | Google ScholarSee all References described chondral delaminations in soccer players. However, those lesions were already at time of operation open chondral defects and according to the above proposed CD-classification grade 4 to 5. In their radiology paper from 2005, Kendell et al37x37Kendell, S.D., Clyde, A.H., Rampton, J.W., Garrett, W.E., and Higgins, L.D. MRI appearance of chondral delamination injuries of the knee. AJR Am J Roentgenol.2005;
184: 1486–1489 Crossref | PubMed | Scopus (37) | Google ScholarSee all References described 5 patients with chondral delamination but no more precise information about type of surgical treatment was described. Mean patient age was 26.4 (16-37) years, lesion size from 0.5 to 2.5 cm with the locations on medial femoral condyle, trochlea and patella.
Theodorides et al44x44Theodorides, A.A., Williams, A., Guthrie, H., and Church, S. Diagnosis and management of chondral delamination injuries of the knee. Knee. 2019;
26: 647–652 Abstract | Full Text | Full Text PDF | PubMed | Scopus (3) | Google ScholarSee all References were the first to present treatment suggestions for chondral delamination. A case series of 3 patients (12-36 years of age) with knee pain and MRI identified chondral delaminations were presented. Two of the lesions were located in the patella and one on the lateral aspect of the medial femoral condyle. All 3 lesions were treated with bioabsorbable pin fixation.21x21Newberry, W.N., Zukosky, D.K., and Haut, R.C. Subfracture insult to a knee joint causes alterations in the bone and in the functional stiffness of overlying cartilage. J Orthop Res. 1997;
15: 450–455 Crossref | PubMed | Scopus (79) | Google ScholarSee all References The delaminated area was easily recognized at arthroscopy by its swampy character on probing. The condyle patient was mobilized with non-weight bearing for 6 weeks and with static isometric quadriceps exercises undertaken from the outset. Loaded flexion was allowed from 12 weeks. One patellar lesion patient was placed in a range of motion brace 0 to 30° and advised to mobilize weight bearing as tolerated the first 6 weeks. The brace was removed for unrestricted range of flexion while not under load. All 3 patients recovered well clinically and the lesions healed on MRI.44x44Theodorides, A.A., Williams, A., Guthrie, H., and Church, S. Diagnosis and management of chondral delamination injuries of the knee. Knee. 2019;
26: 647–652 Abstract | Full Text | Full Text PDF | PubMed | Scopus (3) | Google ScholarSee all References
A totally loose delaminated cartilage piece can be attached as described by an all arthroscopic suture-bridge fixation with the use of pushlock anchors.45x45Lawrence, J.T.R., Trivedi, V., and Ganley, T.J. All arthroscopic suture-bridge fixation of a delaminated chondral fragment. UPOJ. 2011;
21: 83–86 Google ScholarSee all References
The author of this paper treats the chondral delamination depending on the size of lesion, patient age and level area of the separation, above or in the calcified layer or below the calcified layer. If the chondral delamination has occurred in a child or adolescent with no calcified layer developed, often a small thin wafer of the bone plate may be attached to the delaminated cartilage. If the delamination is not too large, re-fixation with resorbable pins is then an option (Fig. 5Fig. 5A and B).
Fig. 5
A: A drawing of the delaminated area after hematoma evacuation. The area is still soft and moveable and needs to be fixated to the bone. B: The delaminated area has been fixated with resorbable smartnails. Such a fixation may be done in a triangular fashion. C: If large delaminated area, additional corner sutures might be needed. D: A delaminated area has not been treated and one of the corner bridges to surrounding non-delaminated cartilage has been broken. A full thickness area will develop needing more aggressive cartilage repair.
First, the region is emptied from the hematoma by needle aspiration followed by pin fixation, mostly smart nails (ConMed). If the delamination area is large, mini-open surgery may be needed and complimentary osteo-sutures could be used (Fig. 5Fig. 5A and B). If it is not an option to re-fixate (Fig. 5Fig. 5C), just the soft spot area is debrided (Fig. 6Fig. 6A). The lesion area is then debrided as like an ordinary ICRS III lesion. If it is a small lesion, most often bone marrow stimulation is done (Fig. 6Fig. 6B). If it is a larger lesion, an additional scaffold may be used like Hyalofast (ANICA).
Fig. 6
A: If the delaminated area is not suitable for refixation, the delaminated needs to be excised. For small injured areas, excision with a small punch is easily performed. B: A small delamination area is treated with bone marrow stimulation after debridement. A 2 mm burr is used.
Larger defects can be directly treated by chondral fragment implantation like CAIS,46x46Cole, B.J., Farr, J., Winalski, C.S. et al. Outcomes after a single-stage procedure for cell-based cartilage repair: a prospective clinical safety trial with 2-year follow-up. Am J Sports Med. 2011;
39: 1170–1179 Crossref | PubMed | Scopus (196) | Google ScholarSee all References CAFRIMA47x47Brittberg, M. Clinical articular cartilage repair—An up to date review. Annals of Joint. 2018;
3: 1–8 Google ScholarSee all References or Autocart.48x48Lavender, C., Sina Adil, S.A., Singh, V., and Berdis, G. Autograft cartilage transfer augmented with bone marrow concentrate and allograft cartilage extracellular matrix. Arthrosc Tech. 2020;
9: e199–e203 Abstract | Full Text | Full Text PDF | PubMed | Scopus (9) | Google ScholarSee all References Fragments can be harvested from the soft delamination cartilage. Dehydrated, micronized allogeneic cartilage that can be implanted with platelet-rich plasma into cartilage defects is also an alternative.49x49Hirahara, A.M. and Mueller, K.W. Jr. BioCartilage: a new biomaterial to treat chondral lesions. Sports Med Arthrosc Rev.2015;
23: 143–148 Crossref | PubMed | Scopus (36) | Google ScholarSee all References After debridement, it can be noted that the surrounding cartilage has regained its elasticity.
It is very important to understand that even though MRI did not show any pathology, a patient with a localized knee pain, could have a localized chondral delamination. In cases with sustainable pain, careful probing of the cartilage areas is mandatory.
Discussion
Patients seeking orthopedic evaluation due to joint pain, post-trauma or without traumatic history are most often examined by MRI. If nothing is found on MRI, the patients are scheduled for physiotherapy. However, if in spite of long time training, the patient still is in pain, often the next step is an arthroscopy. Prior to an arthroscopy, one may add a scintigraphic evaluation like a pure technetium scan or a SPECT.50x50Hirschmann, A. and Hirschmann, M.T. Chronic knee pain: clinical value of MRI versus SPECT/CT. Semin Musculoskelet Radiol. 2016;
20: 3–11 Crossref | PubMed | Scopus (13) | Google ScholarSee all References Such a scan may show an increased uptake locally in the joint which will help the surgeon performing the arthroscopy to focus on the area of scintigraphic uptake. The incidence of chondral delamination injuries of the knee has not been reported in the literature. Already in 1985, Hopkinson et al51x51Hopkinson, W.J., Mitchell, W.A., and Curl, W.W. Chondral fractures of the knee. Cause for confusion. Am J Sports Med. 1985;
13: 309–312 Crossref | PubMed | Scopus (44) | Google ScholarSee all References described a group of patients presenting with meniscal symptoms of who, on arthroscopic examination, had chondral fractures of the medial or lateral femoral condyle. The authors felt it was important to discuss the chondral fracture so that the orthopedic surgeon could be aware this injury type.51x51Hopkinson, W.J., Mitchell, W.A., and Curl, W.W. Chondral fractures of the knee. Cause for confusion. Am J Sports Med. 1985;
13: 309–312 Crossref | PubMed | Scopus (44) | Google ScholarSee all References Since then, better diagnostics have been introduced with different MRI sequences but still chondral delaminations may be difficult to diagnose. Delamination injuries of cartilage can lead to significant morbidity if they are not treated early. This means that delay in finding such lesions may lead to early OA and more aggressive treatments. If a patient is claiming a significant pain in certain degrees of joint flexion, suspicion of local delamination is adequate and an arthroscopy is indicated, though the MRI is negative.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Declaration of competing interest
I am a member of the advisory board for Episurf Medical AB. I have been on the speaker's bureau for Arthrex during 2021. I have consultancies for Xintela AB and for Finceramica during 2021. I am editor in chief of Journal CARTILAGE.
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